A pigment for increasing the hiding power of white coatings and a white coating having high hiding power

Abstract

The present invention discloses a pigment for increasing the hiding power of white coatings, comprising aluminum pigment and titanium dioxide pigment with a mass ratio of 0.1 - 0.2:8.7 - 8.9; by mass percentage, the aluminum pigment comprises 69 - 72% of aluminum flakes, 20 - 25% of hydrodesulfurized kerosene, 5 - 10% of aromatic solvent, and 0 - 2% of oleic acid. This pigment replaces titanium dioxide with aluminum pigment within a specific particle size range without increasing the total amount of pigment. At the same time, the present invention also discloses a white coating comprising this pigment, which improves the hiding power of the white coating without increasing the solid content of the white coating by relying on the excellent hiding performance of the aluminum pigment.

Description

Technical Field

[0001] The present invention relates to the technical field of pigments. More specifically, it relates to a pigment for increasing the hiding power of white coatings and a white coating with high hiding power. Background Art

[0002] In the prior art, the hiding effect of white coatings is mainly achieved by adding titanium dioxide and color pastes. If one wants to improve the hiding power of white coatings, the content of color pastes or titanium dioxide needs to be increased. However, adding color pastes will change the color of white coatings, and increasing the content of titanium dioxide will increase the solid content of white coatings, resulting in the coatings not meeting the requirements of customers.

[0003] Therefore, there is a need to provide a pigment that can both improve the hiding power of white coatings and does not increase the solid content of the coatings. Summary of the Invention

[0004] An object of the present invention is to provide a pigment for increasing the hiding power of white coatings. The pigment includes aluminum pigment and titanium dioxide pigment with a certain mass fraction, which can effectively increase the hiding power of white coatings without affecting the solid content of the coatings containing the pigment.

[0005] Another object of the present invention is to provide a white coating with high hiding power containing the above pigment and its preparation method.

[0006] To achieve the above first object, the present invention adopts the following technical solution:

[0007] A pigment for increasing the hiding power of white coatings includes aluminum pigment and titanium dioxide pigment with a mass ratio of 0.1 - 0.2:8.7 - 8.9; by mass percentage, the aluminum pigment includes 69 - 72% of aluminum flakes, 20 - 25% of hydrodesulfurized kerosene, 5 - 10% of aromatic solvents, and 0 - 2% of oleic acid.

[0008] Among them, the particle size of the aluminum pigment is 1 - 13 μm.

[0009] Optionally, by mass percentage, the titanium dioxide pigment includes 97 - 100% of titanium dioxide, 0 - 1% of zirconium oxide, 0 - 1% of tin dioxide, and 0 - 1% of aluminum hydroxide.

[0010] To achieve the above second object, the present invention adopts the following technical solution:

[0011] A white paint with high hiding power, comprising the following raw materials in parts by weight: 8-10 parts of the above-mentioned pigment, 5-10 parts of amino resin, 0.1-0.4 parts of amine compound, 5-10 parts of polyester resin, 15-25 parts of acrylic emulsion, 1-2 parts of acrylic resin, 1-3 parts of other additives, 0.20-0.30 parts of color paste, 0.1-0.3 parts of dodecyl phosphoric acid, 30-40 parts of solvent.

[0012] Preferably, the color paste includes black paste and yellow paste.

[0013] Preferably, the other additives include at least one of dispersant, ultraviolet absorber, thickener and polyether polyol.

[0014] Preferably, the solvent includes at least one of pure water, isooctanol and hydrocarbon solvent.

[0015] Preferably, the amino resin is alkylated melamine formaldehyde resin.

[0016] Preferably, the amine compound is 2-(dimethylamino)ethanol.

[0017] Preferably, the polyester resin has a solid content of 70-75%, a viscosity of Z2-Z5, a color number of 2-4, and an acid value of 26.9-30.9 mg KOH / g.

[0018] Preferably, the acrylic emulsion has a solid content of 45-50%, a pH of 5.9-6.5, a particle size of 270-330 nm, an acid value of 22-26 mg KOH / g, and a viscosity of 5000-50000 mPa·s.

[0019] The present invention also provides a preparation method of the above white paint, comprising the following steps:

[0020] Add 5-10 parts of amino resin into container A, and then sequentially add 23-26 parts of solvent, 0.1-0.4 parts of amine compound, 5-10 parts of polyester resin, 8.7-8.9 parts of titanium dioxide pigment under stirring until the fineness ≤ 20 μm; continue to add 15-25 parts of acrylic emulsion and 0.5-1.5 parts of other additives under stirring;

[0021] Add 0.1-0.2 parts of aluminum pigment and 2-4 parts of solvent into container B, stir, and then add 1-2 parts of acrylic resin and 0.5-1.5 parts of other additives under stirring to obtain aluminum paste;

[0022] While stirring, add the aluminum paste into container A at a rate of 20 kg / min and stir until the fineness is ≤ 20 μm; add 0.1 - 0.3 parts of dodecyl phosphate, 0.20 - 0.30 parts of color paste and 5 - 10 parts of solvent under stirring to obtain the product.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention provides a pigment containing aluminum pigment and titanium dioxide. Without increasing the total amount of the pigment, the aluminum pigment within a specific particle size range is used to replace titanium dioxide. When this pigment is used in white coatings, relying on the excellent covering performance of the aluminum pigment, the covering power of the white coating is improved without increasing the solid content of the white coating. Specific embodiments

[0025] To illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0026] In the case of clarifying and explaining the object of the present invention through the following embodiments, the components of the composition are explained with weight parts as the general standard. Without special instructions, for the sake of simplicity, the "parts" described in the embodiments of the present invention have the same meaning as weight parts. The present invention provides a pigment for increasing the covering power of white coatings, comprising an aluminum pigment and a titanium dioxide pigment with a mass ratio of 0.1 - 0.2:8.7 - 8.9; by mass percentage, the aluminum pigment comprises 69 - 72% of aluminum flakes, 20 - 25% of hydrodesulfurized kerosene, 5 - 10% of aromatic solvent and 0 - 2% of oleic acid; wherein, the particle size of the aluminum pigment is 1 - 13 μm.

[0027] One possible embodiment is that the titanium dioxide pigment comprises 97 - 100% of titanium dioxide, 0 - 1% of zirconium oxide, 0 - 1% of tin dioxide, 0 - 1% of aluminum hydroxide.

[0028] The present invention creatively uses aluminum pigments to replace part of the titanium dioxide pigments, thereby improving the hiding power of the pigments without increasing the total amount of pigments. The pigments provided by the present invention have excellent whiteness, tinting strength, hiding power, weather resistance, heat resistance and stable chemical properties. Among them, the aluminum pigments and titanium dioxide pigments can be obtained by commercial purchase. The aluminum pigments include, but are not limited to, ALUMINIUM PASTE 65-388NN, 65-388N, CG-320, TZ-5029N produced by Toyo Aluminium Co., Ltd.; Yasi Da YSP-16AS, Yasi Da LX-9800A, etc. The titanium dioxide pigments include, but are not limited to, TIPAQUE CR-97(25kg) produced by Ishihara Chemical Co., Ltd., R-216, R-2196+, R-215, R-2196, R-217, R-213, R-2219, R-219, R-218 produced by Zhonghe Huayuan Titanium Dioxide Co., Ltd., cr-506 produced by Citic Titanium Industry Co., Ltd., etc.

[0029] The present invention also provides a white paint with high hiding power, which comprises the following raw materials in parts by weight: 8-10 parts of the pigments as described above, 5-10 parts of amino resin, 0.1-0.4 parts of amine compound, 5-10 parts of polyester resin, 15-25 parts of acrylic emulsion, 1-2 parts of acrylic resin, 1-3 parts of other additives, 0.20-0.30 parts of color paste, 0.1-0.3 parts of dodecyl phosphoric acid, and 30-40 parts of solvent.

[0030] Generally, white paints have poor hiding power because they do not contain color paste or contain less color paste. The white paint provided by the present invention contains the above-mentioned pigments. The laying characteristics of the aluminum pigments in the pigments make it have excellent hiding power, and while significantly improving the hiding power of the white paint, it will not affect the color of the white paint.

[0031] In a possible embodiment, the color paste includes black paste and yellow paste. The combined use of black paste and yellow paste can meet the requirements of consumers for the brightness and blue-green value of the paint.

[0032] In a possible embodiment, the other additives include at least one of a dispersant, an ultraviolet absorber, a thickener and a polyether polyol.

[0033] The dispersant has good affinity with the pigment, can quickly wet the surface of the pigment and produce a strong adsorption effect. At the same time, it also has good compatibility with the main resin and acrylic emulsion, reducing the possibility of the coating system flocculating or aggregating again, making the coating system not delaminate for a long time, and having stable viscosity and dispersibility, ensuring the hiding power and stability during the use of the coating. Those skilled in the art can also purchase suitable dispersants according to needs, including but not limited to SURFYNOL 440, Tu Yile 440, etc. produced by Air Products Changzhou Co., Ltd.

[0034] The thickener can make the coating system have appropriate viscosity, including but not limited to ADEKANOL UH-814N produced by ADEKA (Shanghai) Trading Co., Ltd., SN THICKENER N-1 produced by Nopco.

[0035] The ultraviolet absorber can absorb ultraviolet rays in sunlight without changing itself, preventing the yellowing of the paint film. The ultraviolet absorber can be but not limited to TINUVIN 123, TINUVIN384-2 produced by BASF Applied Chemicals Co., Ltd., Chisorb 523 produced by DOUBLE BOND CHEMICAL.

[0036] In a possible implementation manner, the solvent includes pure water, isooctanol and hydrocarbon solvent. The solvent formulation provided by the present invention is beneficial to balancing the viscosity of the coating and the stability of storage.

[0037] In the present invention, the amino resin is an alkylated melamine formaldehyde resin. This amino resin has good compatibility, stability, good hardness, high gloss and good chemical resistance. According to mass percentage, this amino resin includes not less than 70% of amino monomers and less than 30% of butanol. During implementation, a suitable amino resin can be obtained through commercial purchase, including but not limited to CYMEL 250, CYMEL 370, etc. produced by Axalta Coating Systems (Shanghai) Co., Ltd.

[0038] In a possible implementation manner, the amine compound is 2-(dimethylamino)ethanol. The amine compound includes but not limited to dimethylethanolamine produced by BASF Applied Chemicals Co., Ltd., Dow Multifunctional Additive AMP-95.

[0039] In a possible embodiment, the solid content of the polyester resin is 70 - 75%, the viscosity is Z2 - Z5, the color number is 2 - 4, and the acid value is 26.9 - 30.9 mg KOH / g. The polyester resin can be formed by polymerizing 70 - 75% of polyester resin monomers and 25 - 30% of 2 - ethyl - 1 - hexanol. This polyester resin can endow the coating with good flexibility, wettability, dispersibility, adhesion and physical and mechanical properties, and the coating film is plump. The polyester resin includes but is not limited to PRS - 1045 RESIN, NEOREL R - 9603 produced by Nippon Paint Co., Ltd.

[0040] In a possible embodiment, the solid content of the acrylic emulsion is 45 - 50%, the PH is 5.9 - 6.5, the particle size is 270 - 330 nm, the acid value is 22 - 26 mg KOH / g, and the viscosity is 5000 - 50000 mPa·s. Preferably, this acrylic emulsion includes 45 - 50% by mass of acrylic monomers and 50 - 55% of propylene glycol - methyl ether. This acrylic emulsion can endow the white coating with good light and color retention, water resistance, chemical resistance, weather resistance, heat resistance, including but not limited to EMA - 1015S, EMA - 1032 RESIN produced by Nippon Paint.

[0041] The preparation method of the above - mentioned white coating in the present invention includes the following steps:

[0042] Add 5 - 10 parts of amino resin into container A, and then successively add 23 - 26 parts of solvent, 0.1 - 0.4 parts of amine compound, 5 - 10 parts of polyester resin, 8.7 - 8.9 parts of titanium dioxide pigment under stirring until the fineness ≤ 20 μm; continue to add 15 - 25 parts of acrylic emulsion and 0.5 - 1.5 parts of other additives under stirring;

[0043] Add 0.1 - 0.2 parts of aluminum pigment and 2 - 4 parts of solvent into container B, stir, and then add 1 - 2 parts of acrylic resin and 0.5 - 1.5 parts of other additives under stirring to obtain aluminum paste;

[0044] Add the aluminum paste into container A at a rate of 20 kg / min under stirring until the fineness ≤ 20 μm; add 0.1 - 0.3 parts of dodecyl phosphate, 0.20 - 0.30 parts of color paste and 5 - 10 parts of solvent under stirring, and then it is obtained.

[0045] Among them, the solvent added into container A is selected from at least one of isooctanol, water and hydrocarbon - based solvents, the solvent added into container B is isooctanol, and the finally added solvent is pure water. The other additive added into container A is a dispersant, and the other additives added into container B are selected from at least one of polyether polyol, thickener, and ultraviolet absorber.

[0046] Next, the present invention will describe the technical solution in conjunction with specific embodiments.

[0047] Preparation Example

[0048] Preparation Examples 1-4

[0049] In Preparation Examples 1-4, the composition of the pigment is shown in Table 1. Among them, the particle size of the aluminum pigment ALUMINIUM PASTE 65-388NN produced by Toyo Aluminium Co., Ltd. is 1-13 μm. The aluminum pigment includes 69-72% aluminum flakes, 20-25% hydrodesulfurized kerosene, 5-10% aromatic solvent, and 0-2% oleic acid.

[0050] Table 1 Composition of Pigments in Preparation Examples 1-4

[0051]

[0052] Preparation Examples 5-8

[0053] In Preparation Examples 5-8, the composition of the pigment is shown in Table 2. Among them, the pigment in Preparation 5 does not contain aluminum pigment. The proportion of aluminum pigment in the pigment of Preparation Example 6 is too large. The particle size of the aluminum pigment in the pigments of Preparation Examples 7 and 8 is too large, exceeding the range of 1-13 μm. The particle size of the aluminum pigment ALUMINIUM PASTE 93-0647 produced by Toyo Aluminium Co., Ltd. is 20-30 μm. The aluminum pigment includes 69-72% aluminum flakes, 20-25% hydrodesulfurized kerosene, 5-10% aromatic solvent, and 0-2% oleic acid; the particle size of the aluminum pigment ALUMINIUM PASTE 3200 produced by SCHIENK Aluminum Powder Company is 30-50 μm. The aluminum pigment includes 69-72% aluminum flakes, 20-25% hydrodesulfurized kerosene, 5-10% aromatic solvent, and 0-2% oleic acid.

[0054] Table 2 Pigment Composition in Preparation Examples 5-8

[0055]

[0056] Example

[0057] The preparation process of the white paint in the example is as follows:

[0058] A. Add 10 parts of amino resin to the main cylinder, start stirring at 400-600 rpm.

[0059] While stirring, add 3 parts of isooctanol, 18 parts of pure water, and 3 parts of hydrocarbon solvent. After 5 minutes, add 0.2 parts of amine compound. After stirring for 5 minutes, add 10 parts of polyester resin, continue stirring for 5 minutes, add titanium dioxide pigment, and stir at 1500-200 rpm for 30 minutes until the particle size ≤ 20 μm;

[0060] Then continue to add 25 parts of acrylic emulsion under stirring, add 1 part of dispersant after 5 minutes, and continue to stir for 5 minutes;

[0061] B. Add 3 parts of isooctanol and aluminum pigment in another container. After adding, stir at a speed of 100 - 400 rpm for 10 minutes. While stirring, add 1 part of acrylic resin, 0.54 part of polyether polyol, 0.5 part of ultraviolet absorber and 0.2 part of thickener and stir for 10 minutes to obtain aluminum paste;

[0062] C. While stirring (500 - 900 rpm) in the main cylinder, use a feeding funnel to add aluminum paste at a feeding speed of 20 kg / min. After adding, stir for 20 minutes and confirm that the fineness ≤ 20 μm.

[0063] D. While stirring, add 0.2 part of dodecyl phosphate and 5 parts of pure water in sequence. After adding, stir at a speed of 500 - 1000 rpm for 5 minutes.

[0064] E. Adjust the pH value to 7.95 - 8.15 and stir for 10 minutes;

[0065] F. Add 0.05 part of black paste and 0.18 part of yellow paste to finely adjust the color to be qualified; adjust the viscosity to be qualified with 10.13 parts of pure water.

[0066] Apply the pigments in Preparation Examples 1 - 4 to the white coatings in Examples 1 - 4, and their specific components are shown in the following table.

[0067] Table 3 Composition of White Coatings in Examples 1 - 4

[0068]

[0069]

[0070] Comparative Examples 1 - 4

[0071] In Comparative Example 1, the pigment in Preparation Example 5 was used to replace the pigment in Example 1, and other components were the same as those in Example 1; in Comparative Example 2, the pigment in Preparation Example 6 was used to replace the pigment in Example 1, and other components were the same as those in Example 1; in Comparative Example 3, the pigment in Preparation Example 7 was used to replace the pigment in Example 1, and other components were the same as those in Example 1; in Comparative Example 4, the pigment in Preparation Example 8 was used to replace the pigment in Example 1, and other components were the same as those in Example 1.

[0072] Performance Measurement

[0073] Test the performance of the white coatings in Examples 1 - 4 and Comparative Examples 1 - 4, and the results are shown in Tables 4 and 5.

[0074] Performance test results of white coatings in Examples 1-4 in Table 4

[0075]

[0076]

[0077] The results in Table 4 show that in the present invention, by adding the pigments in Preparation Examples 1-4, without changing the solid content and color of the white coating, the black-and-white hiding power is strong, and there is no obvious abnormality in the visual color difference, which indicates that the pigments provided by the present invention improve the hiding power of the white coating.

[0078] Performance test results of white coatings in Comparative Examples 1-4 in Table 5

[0079]

[0080]

[0081] The results in Table 5 show that when the pigment in Comparative Example 1 does not contain aluminum pigment but contains black paste, the white coating becomes significantly black; when the aluminum pigment content in the pigment in Comparative Example 2 is too high, it will also cause the white coating to become significantly black; and when the particle size of the aluminum pigment is too large, obvious flashing particles will appear in the white coatings in Comparative Examples 3 and 4.

[0082] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to enumerate all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A white paint with high hiding power, characterized in that, Raw materials in the following parts by weight: 8 - 10 parts of pigment, 5 - 10 parts of amino resin, 0.1 - 0.4 parts of amine compound, 5 - 10 parts of polyester resin, 15 - 25 parts of acrylic emulsion, 1 - 2 parts of acrylic resin, 1 - 3 parts of other additives, 0.20 - 0.30 parts of color paste, 0.1 - 0.3 parts of dodecyl phosphoric acid, 30 - 40 parts of solvent; The sum of the weight parts of each raw material of the white paint is 100 parts; The pigment includes aluminum pigment and titanium dioxide pigment with a mass ratio of 0.1 - 0.2:8.7 - 8.9; By mass percentage, the aluminum pigment includes 69 - 72% of aluminum flakes, 20 - 25% of hydrodesulfurized kerosene, 5 - 10% of aromatic solvent and 0 - 2% of oleic acid, and the particle size of the aluminum pigment is 1 - 13 μm; By mass percentage, the titanium dioxide pigment includes 97 - 100% of titanium dioxide, 0 - 1% of zirconium oxide, 0 - 1% of tin dioxide, 0 - 1% of aluminum hydroxide; At least one of a dispersant, an ultraviolet absorber, a thickener and a polyether polyol is included in the other additives.

2. The white paint according to claim 1, characterized in that, The color paste includes a black paste and a yellow paste.

3. The white paint according to claim 1, characterized in that, At least one of pure water, isooctanol and hydrocarbon solvent is included in the solvent.

4. The white paint according to claim 1, characterized in that, The amino resin is an alkylated melamine formaldehyde resin.

5. The white paint according to claim 1, characterized in that, The amine compound is 2-(dimethylamino)ethanol.

6. The white paint according to claim 1, characterized in that, The solid content of the polyester resin is 70 - 75%, the viscosity is Z2 - Z5, the color number is 2 - 4, and the acid value is 26.9 - 30.9 mg KOH / g.

7. The white paint according to claim 1, characterized in that, The solid content of the acrylic emulsion is 45 - 50%, the pH is 5.9 - 6.5, the particle size is 270 - 330 nm, the acid value is 22 - 26 mg KOH / g, and the viscosity is 5000 - 50000 mPa·s.

8. A method for preparing the white paint according to any one of claims 1-7, characterized in that, It includes the following steps: Add 5 - 10 parts of amino resin into container A, and then sequentially add 23 - 26 parts of solvent, 0.1 - 0.4 parts of amine compound, 5 - 10 parts of polyester resin, 8.7 - 8.9 parts of titanium dioxide pigment under stirring until the fineness ≤ 20 μm; continue to add 15 - 25 parts of acrylic emulsion and 0.5 - 1.5 parts of other additives under stirring; Add 0.1 - 0.2 parts of aluminum pigment and 2 - 4 parts of solvent into container B, stir, and then add 1 - 2 parts of acrylic resin and 0.5 - 1.5 parts of other additives under stirring to obtain an aluminum paste; Add the aluminum paste into container A at a rate of 20 kg / min under stirring, stir until the fineness ≤ 20 μm; add 0.1 - 0.3 parts of dodecyl phosphoric acid, 0.20 - 0.30 parts of color paste and 5 - 10 parts of solvent under stirring to obtain the product.

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